Hydrodynamic unit for power transmission

ABSTRACT

Power transmission in which the input rotor of a hydrodynamic torque-transmitting unit and a rotatable transmission input are selectively clutched and unclutched to control power flow through the unit. Controls associated with a gear selector mechanism for forward and reverse gearing effect the momentary disconnection of the input rotor and the transmission input when shifting gears. Disc brakes selectively engageable with the differential input provide vehicle service brakes. The housing of the torquetransmitting unit is rigidly connected to the transmission input by deforming a portion of the housing into appropriate openings formed in the transmission input.

United States Patent 1151 3,659,414 Hause 1 51 May 2, 1972 s41HYDRODYNAMIC UNIT FOR POWER 2,453,811 11/1948 Pennington 192/311TRANSMISSION 3,250,222 5/1966 Zeidler ..60/54 X 3,326,066 6/1967Murphy.... ....192/3.33 [721 lnvemm- 3,384,209 5/1968 Murphy ..192/3.33[73] Assignee: General Motors Corporation, Detroit, Mich. PrimaryExaminer-Edgar W. Geoghegan Filed I I Nov 23 970 Attorney-W. E. Finken,A. M. Heiter and Charles R. White 211 App]. No.: 91,812 57 ABSTRACTRelated Us m m Data Power transmission in which the input rotor of ahydrodynamic torque-transmitting unit and a rotatable transmission input[62] D1v1s1on of Ser. No. 805,745, Mar. 10, 1.969, a are selectivelyclutched and unclutched to control power flow 315901966? through theunit. Controls associated with a gear selector mechanism for forward andreverse gearing effect the momen- [52] U.S.Cl. ..60/54, 220/5 tarydisconnection of the input rotor and the transmission 2; Field Se h 3 2?3 input when shifting gears. Disc brakes selectively engageable 1 o withthe differential input rovide vehicle service brakes. The

h u o e o d1 d ousmg o e torque-transmitting un1t1s r1g1 y connecte to[56] Reta-"Ices and the transmission input by deforming a portion of thehousing UNITED STATES PATENTS into appropriate openings formed in thetransmission input.

1,689,245 10/1928 Klimek 192/321 7 Claims, 1 Drawing Figure o\,(, J 33,i .11; i i a 1 121 19 a a I; a o o E 1 '1, 5 1 1 M 37 I i Q .fl r a 55 Ha! 9.4 g 1 1/ .97

' HYDRODYNAMIC UNIT FOR POWER TRANSMISSION This is a division ofapplication Ser. No. 805,745, filed Mar. 10, 1969 now US. Pat. No.3,590,966.

This invention relates to power transmissions and more par ticularly toa transmission featuring a new and improved connection between thetransmission input and a hydrodynamic unit housing, unique forward andreverse gearing driven by the unit and controls therefor, and anadvanced clutch and controls for selectively coupling and uncoupling thehydrodynamic unit rotor and the transmission input.

In low-power-to-weight vehicles, such as the small economy typepassenger car, multi-stepped manual transmissions are generally employedto provide a range of output torques needed for efficient vehicleoperation. Due to the cost, complexity, and space requirements,automatic torque converter transmissions generally have not beenemployed in such vehicles.

This invention provides a highly efficient torque convertertransmission, which is inexpensive, uncomplicated, and sufficientlysmall to be effectively employed in the low-power-toweight vehiclesmentioned above. Although this invention is primarily for smallervehicles as mentioned above, it can be employed in larger vehicles suchas the standard six-passenger car.

The cost of this transmission is materially reduced by utilizing a newand improved connection between the flywheel and converter housing.Furthermore, simplified forward and reverse gearing is provided andthere are new and improved controls for eliminating power flow throughthe converter when the transmission gearing is conditioned for neutral.In this invention, forward and reverse transmission gears mesh directlywith the differential input gear, thereby providing a reduction intransmission size and weight. In this invention the converter pump isselectively connected to the flywheel by improved clutch and controlsfor forward and reverse drives.

An object of this invention is to provide a new and improvedtransmission featuring a hydrodynamic unit selectively driving forwardor reverse gearing meshing directly with difi'erential input.

Another object of this invention is to provide a transmission having ahydrodynamic unit and a new and improved connection between a rotatablecomponent of the unit, such as a hydrodynamic unit rotor.

Another object of this invention is to provide a new and improvedconnection between an annular transmission input and a metallic torqueconverter housing in which a portion of the housing is deformed into anannular groove and spaced openings to rigidly connect these parts in anassembly.

Another object of this invention is to provide a transmission includinga hydrodynamic unit having an input rotor selectively connected to thetransmission input by a new and improved clutching mechanism andcontrols so that the unit can transmit input torque therethrough.

Another object of this invention is to provide a new and improved torqueconverter transmission having a converter pump selectively connectedwith an input member by new and improved clutch and controls and inwhich forward and reverse gearing, selectively clutched to a converterdriven shaft, is directly connected to drive a differential input gear.

These and other objects of the invention will become more apparent fromthe following detailed description and from the drawing in which:

The FIGURE is a side view partly in section of a torque convertertransmission and controls thereof.

As shown in the FIGURE, engine crank shaft 1,journaled in bearings 3 isdrivingly connected to a flywheel 5 located in case 7. The flywheel hasan annular rim 9 with an outwardly facing circular groove 11 machinedtherein and a series of spaced holes 13. The holes are drilled radiallyinwardly from the bottom of the groove toward the rotational axis of theflywheel 5 and a connected torque converter 15. The torque converter hasa metallic shell-like housing 17, which has an annular side that fitsover the rim of the flywheel. The annular portion of the side of thehousing which extends over the groove 11 and radial holes 13 is deformedinto the grooves and holes to rigidly assemble the housing to theflywheel.

This connection may be accomplished by utilizing an electromagneticforming process. The housing is slipped on the flywheel and held inplace by a fixture and then placed inside an electromagnetic formingcoil. Upon discharge of sutficient electrical energy through the coil,from a capacitor bank, for example, the portion of the housing alignedwith the groove and holes is swaged simultaneously into the groove andholes by magnetic forces emanating from the coil to rigidly connect theparts. The annular seal 18 disposed between the flywheel and the housing17 makes this assembly fluid-tight. If desired, the assembly can be madeemploying a mechanical rolling operation with the holes staked fortorsional rigidity.

The torque converter has a pump 19, a turbine 21 and a stator 23 bladedin a conventional manner for the circulation of oil supplied to theconverter by a supply passage, not shown. A one-way brake connects thestator to a ground sleeve 24.

A clutch unit, which is preferably operated by engine oil, is employedto selectively connect or disconnect the flywheel and the pump; thisunit comprises an annular, longitudinally movable friction plate 25which has spaced tabs or teeth on the inner diameter which fit intocorresponding spaced and longitudinally extending slots 29 formed in theouter shell of the pump thereby providing a spline-like connection.There is also an annular piston 31 disposed in the converter housinghaving an inner annular shoulder with a seal 33 molded thereon. Thisseal slidably mounts the piston on the inner cylindrical shoulder of thehousing 17 as shown. The piston also has an outer annular shoulder 34and annular seal 35 which slidably contact an annular internal portionof the housing to provide a chamber 37 between the end of housing 17 andpiston 31. This chamber receives a pressure oil which effectsdisplacement of the piston so that the radially extending annular applysurface 38 of the piston will contact the friction plate 25 and move itinto frictional engagement with the transverse end portion of theflywheel to drivingly connect the flywheel and pump. When chamber 37 isopen to exhaust, converter pressure provides the releasing force forpiston 31 and the clutch 25. As shown in the FIGURE the outer end of thepiston has extending tangs or fingers 39, which slidably engage withsplines on the outer periphery of the flywheel. The piston only movesabout 0.015 inch between full apply and full release and is alwaysguided. The piston and housing have a similar radius of curvature toprovide a compact arrangement of parts. The housing 17 further has acylindrical sleeve 42 that extends away from the torque converter and isoperatively connected to the drive gear of fluid pump 44. Because themetal in the converter housing 17 extends into the axial holes in theflywheel, there is sufiicient torsional rigidity to permit the engineand flywheel to drive the pump through the housing.

Chamber 37 is hydraulically connected by a passage in the housing to anannular groove 40 formed in a support sleeve 41, that supports rotatablehousing 17 and rigidly connects the ground sleeve to case 7. Annulargroove 40 is connected by a suitable passage 43 to a control valve 45,which will be later described. The turbine 21 has a hub joumaled in theflywheel and is drivingly connected by splines 47 to a powertransmitting shaft 49. This shaft is coaxial with the flywheel andtorque converter and extends from the torque converter through forwardand reverse drive gears 53 and 55 respectively located adjacent to oneanother and rotatably mounted on the shaft. The shaft terminates in anend extension having spaced flanges 59 arranged to slidably receive apin 61 therebetween secured to a crank member 63 which is supported incase 7 for turning with respect to axis 64. This crank member is turnedby link 65 operatively secured to a conventional shift lever, not shown.The shaft 49 carries a stepped tooth dog clutch element 67 that is fixedto the shaft and is accommodated by recess 69 formed between the gears53 and 55. These gears are formed with internal clutching teeth 71 and73 respectively which are drivingly engageable with the stepped toothdog clutch element to connect the shaft 49 to either gear 53 or gear 55.In the position shown in the drawing,

the dog clutch element is in the neutral position and no power can flowfrom the shaft to either gear.

The shaft 49 can be selectively connected to either gear 53 or 55 byappropriate axial movement of the shaft from the illustrated position inresponse to actuation of the shift lever and the correspondinglongitudinal movement of connected link 65 and rotation of crank 63. Asshown, the shaft carries a spring biased ball detent 75, whose ballmembers fit into anyone of the three side-by-side spaced grooves 77 toreleasably hold the shaft in an adjusted position. When the shaft 49 ismoved in either direction from its neutral position, illustrated in thedrawing, the teeth of the dog clutch element engage the appropriateclutching teeth of the selected gear 53 or 55 to thereby drivinglyconnect the shaft 49 with the selected gear.

Gear 53, providing a forward drive gear, meshes with gear 79 of adifferential drive 81, which is the subject of US. Pat. No. 3,520,213issued July 14, 1970 to Gilbert K. Hause and Clifford C. Wrigley andthis differential is only briefly described here.

The gear 55 meshes with an idler not shown, which in turn meshes withdifferential input gear 79 to provide a reverse drive. As shown, gear 79has transverse openings into which the inner ends of a pair of axleshafts 83 and 85 are rotatably journaled. These shafts extendlongitudinally as does shaft 49 and have meshing spur gears 87 and 89 toprovide for differential speeds of the drive wheels when the vehicleusing this transmission negotiates a turn. To provide a compact powerpackage, axle shaft 85 is disposed through engine cam shafi 91 which isdriven by timing gear 93. i

In this invention disc brakes are employed on opposite sides of the gear79 to provide vehicle service brakes. As shown, each brake assemblycomprises a brake shoe 95, hydraulically actuated piston 97 and spring99. Eachshoe comprises a fric-- tion liner secured to a plate movablymounted in fixed caliper 100. The spring 99 is disposed at the rear ofeach piston,

mounted in a bore in the caliper, provides a low force to lightly engagethe shoe with the friction surface of gear 79 to thereby provide amechanism for automatically adjusting the brakes as they wear. Theparasitical drag of the lining on the friction surface of the gear issufliciently low so that it can be disregarded. The brakes are operatedin a lubricant for improved cooling. As diagrammatically illustrated,the pistons are hydraulically connected to a master cylinder 101 so thatthe brakes are applied when the brake pedal 103 is depressed and so thatthey are released when the brake pedal is released.

The control valve 45 has a valve element 105shiftable to direct fluid toand away from the piston chamber 37. As shown, the valve element has aflanged operator end portion which slidably receives the extension 106of crank 63. In the neutral position shown, the valve element blocks thesupply of fluid, fromthe pump 44 fed to the valve through passage 107.With no pressure in chamber 37 the clutch plate will be disengaged byconverter supply pressure. in neutral, both the converter and gearclutches are disengaged to provide a no-torque neutral.

In operation, forward drive is selected by moving link 65 to the rightthereby turning crank 63 on pivot 64 clockwise. Crank pin 61 will rideupwardly between flanges 59 and also push shaft 49 in toward the crankshaft with splines 47 permitting this movement.

The dog clutch element 67 engages clutching teeth 71 to lock the forwardgear 53 to the shaft 49. At the same time, the valve element is shiftedto a forward drive position with the center land blocking exhaust 109and the passage 43 open to the passage 107. Fluid pressure is admittedto chamber 37 and the clutch isapplied to connect the pump to theflywheel. Under these conditions the torque converter is operative totransmit and multiply torque to shaft 49. Power flows through shaft 49through the forward drive gear 53 to differential gear 79 which runspartially submerged in oil. Power then flows to the axle shafts 83 and85'. Reverse is selected by pushing link 65 toward the converter to turnthe crank counterclockwise with respect to pivot 64. The crank slidesshaft 49 to the right so that dog clutch element 67 will drivinglyengage the reverse gear 55 and also move the valve element through aneutral, exhaust position to a third position in which chamber 37 isagain charged with fluid under pressure. This momentary interruption ofconverter operation when shifting between forward and reverse causesshaft 49 and the gear 79 to decelerate and prevents a sudden torquereversal on the differential input gear. 7

Springs 99 apply forces only sufficient to maintain the shoes in lightcontact with the lubricated annular friction surfaces of the largetransfer or difierential gear 79 and without removing the oil filmthereon. This provides for improved braking since the shoes will effecthigh capacity braking action as soon as pedal 103 is depressed. Thelubricant in the housing is at least suflicient to cover the frictionsurfaces of the brake shoes.

It willbe appreciated that this invention provides an improved powerpackage with an advanced torque converter design, improved transfergearing and also advanced braking as well as the other advancements andimprovements set forth above. Although a particular embodiment of thisinvention is shown and described, it will be understood that this ismerely illustrative of the invention and other modifications can bereadily made. My invention is defined in the claims which follow.

I claim:

1. In a power transmission, an input member, a hydrodynamic unitcomprising a housing and input rotor means and output rotor means,connecting means drivingly connecting said housing to said input rotormeans, torquetransmitting means operatively connected to said outputrotor means, said input member having a cylindrical outer surface,recess means formed in said input member which extend inwardly andradially from said cylindrical outer surface thereof, said housinghaving an extending portion which fits closely over said cylindricalouter surface of said input member, and said extending portion of saidhousing having integral and inwardly extending projections which extendradially. from the inside of said housing into said recess means torigidly secure said input member to said housing.

2. In a power transmission, an input member, a hydrodynamic unitoperatively connected to said input member, torque-transmitting meansoperatively connected to said hydrodynamic unit, said hydrodynamic unithaving a rotatable member formed with a curved extension, said inputmember having a curved extension, one of said extensions being nestedwithin the other of said extensions, and connecting means for rigidlyjoining said extensions including recess means formed in one of saidextensions and integral projecting means formed in the other of saidextensions and extending radially into said reces means.

3. The power transmission of claim 2 wherein said recess means is anannular groove formed in one of said extensions and said projectingmeans is an annular indentation formed in the other of said extensions.

4. The power transmission of claim 2 wherein said recess means comprisesan annular groove and inwardly extending spaced holes which leadinwardly from the bottom surface of said groove, and said projectingmeans comprising an annular depression and a series of projectionsformed from the material of said associated extension disposed in saidgroove and said holes.

5. The power transmission of claim 2 wherein said input member is anengine crank shaft with a flywheel secured to the one end thereof, saidcurved extension of said input member being formed by an outerperipheral portion of said flywheel, said recess means comprising anannular groove in the outer peripheral portion of said flywheel, aseries of inwardly extending and spaced holes leading inwardly from thebottom surface of said annular groove, and said projecting meanscomprising an annular depression and a series of projections formed fromthe material of said extension of said rotatable member operativelydisposed in said groove and in said holes respectively to rigidly securesaid extension of said rotatable member to said flywheel, and saidrotatable member and said extension combining with said flywheel toprovide a housing for said hydrodynamic unit.

6. In a power package for a vehicle, rotatable input shaft means havinga flywheel formed at one end thereof, said flywheel having an annularperipheral surface, said peripheral surface having an annular groove andhaving circumferentially spaced holes which extend inwardly from thebottom of said groove into said flywheel, a torque transmittinghydrodynamic unit having a rotatable outer shell member, said shellmember having an annular extending portion which fits closely over theouter periphery of said flywheel and which cooperates therewith to forma sealed housing for said hydrodynamic unit, said shell member having anannular deformation extending into said annular groove and having spacedinwardly extending projections extending into said holes to rigidlysecure said housing to said flywheel, and annular seal means operativelydisposed between said shell member and said outer peripheral surface ofsaid flywheel to provide for the fluid tight sealing of saidhydrodynamic unit.

7. In a power package, an input member comprising an engine crank shaftwith an annular flywheel formed at one end thereof, a hydrodynamic unitcomprising a rotatable shell member and input rotor means and outputrotor means, said flywheel having an outer annular peripheral surface,annular recess means extending around said peripheral surface of saidflywheel, said shell member of said hydrodynamic unit having an annularextending portion which closely fits over said annular peripheralsurface of said flywheel, and said extending portion of said housinghaving integral projections which extend from the inner side of saidextending portion of said shell member into said recess means to rigidlysecure said flywheel to said shell member so that said flywheel and saidshell member cooperate to form a housing for said hydrodynamic unit.

1. In a power transmission, an input member, a hydrodynamic unitcomprising a housing and input rotor means and output rotor means,connecting means drivingly connecting said housing to said input rotormeans, torque-transmitting means operatively connected to said outputrotor means, said input member having a cylindrical outer surface,recess means formed in said iNput member which extend inwardly andradially from said cylindrical outer surface thereof, said housinghaving an extending portion which fits closely over said cylindricalouter surface of said input member, and said extending portion of saidhousing having integral and inwardly extending projections which extendradially from the inside of said housing into said recess means torigidly secure said input member to said housing.
 2. In a powertransmission, an input member, a hydrodynamic unit operatively connectedto said input member, torque-transmitting means operatively connected tosaid hydrodynamic unit, said hydrodynamic unit having a rotatable memberformed with a curved extension, said input member having a curvedextension, one of said extensions being nested within the other of saidextensions, and connecting means for rigidly joining said extensionsincluding recess means formed in one of said extensions and integralprojecting means formed in the other of said extensions and extendingradially into said recess means.
 3. The power transmission of claim 2wherein said recess means is an annular groove formed in one of saidextensions and said projecting means is an annular indentation formed inthe other of said extensions.
 4. The power transmission of claim 2wherein said recess means comprises an annular groove and inwardlyextending spaced holes which lead inwardly from the bottom surface ofsaid groove, and said projecting means comprising an annular depressionand a series of projections formed from the material of said associatedextension disposed in said groove and said holes.
 5. The powertransmission of claim 2 wherein said input member is an engine crankshaft with a flywheel secured to the one end thereof, said curvedextension of said input member being formed by an outer peripheralportion of said flywheel, said recess means comprising an annular groovein the outer peripheral portion of said flywheel, a series of inwardlyextending and spaced holes leading inwardly from the bottom surface ofsaid annular groove, and said projecting means comprising an annulardepression and a series of projections formed from the material of saidextension of said rotatable member operatively disposed in said grooveand in said holes respectively to rigidly secure said extension of saidrotatable member to said flywheel, and said rotatable member and saidextension combining with said flywheel to provide a housing for saidhydrodynamic unit.
 6. In a power package for a vehicle, rotatable inputshaft means having a flywheel formed at one end thereof, said flywheelhaving an annular peripheral surface, said peripheral surface having anannular groove and having circumferentially spaced holes which extendinwardly from the bottom of said groove into said flywheel, a torquetransmitting hydrodynamic unit having a rotatable outer shell member,said shell member having an annular extending portion which fits closelyover the outer periphery of said flywheel and which cooperates therewithto form a sealed housing for said hydrodynamic unit, said shell memberhaving an annular deformation extending into said annular groove andhaving spaced inwardly extending projections extending into said holesto rigidly secure said housing to said flywheel, and annular seal meansoperatively disposed between said shell member and said outer peripheralsurface of said flywheel to provide for the fluid tight sealing of saidhydrodynamic unit.
 7. In a power package, an input member comprising anengine crank shaft with an annular flywheel formed at one end thereof, ahydrodynamic unit comprising a rotatable shell member and input rotormeans and output rotor means, said flywheel having an outer annularperipheral surface, annular recess means extending around saidperipheral surface of said flywheel, said shell member of saidhydrodynamic unit having an annular extending portion which closely fitsover said annular peripheral surface of said flywheel, and saidextending pOrtion of said housing having integral projections whichextend from the inner side of said extending portion of said shellmember into said recess means to rigidly secure said flywheel to saidshell member so that said flywheel and said shell member cooperate toform a housing for said hydrodynamic unit.